In dishwashers, a circulating pump is used for re-circulating water with detergent to a washing chamber via a circulating path. The circulating pump is usually a centrifugal pump having a motor, an impeller driven by the motor, and a spiral volute with an inlet, an outlet and an impeller chamber for receiving the impeller.
In a traditional centrifugal pump, the wrap angle of the spiral volute is less than 360 degrees and the volute is fixed to the motor by connecting a plurality of mounting portions extending radially from the outer surface of the volute to a bracket of the motor.
For different dishwasher manufacturers, the requirements for the mounting distance between the center line of the outlet of the pump volute and the rotating center of the motor shaft are different, which results in the radial dimensions of the volutes of the pumps also being different. As shown in FIG. 8, the mounting distance M1 of the volute drawn in dashed lines is greater than the mounting distance M2 of the volute drawn in solid lines. Since the wrap angle of the volute is less than 360 degrees, the radial dimension D1 of the volute in dashed lines is also greater than the radial dimension D2 of the volute in solid lines. Thus, a motor supplier has to produce motors having brackets with different radial dimensions to match different volutes of the pumps for different dishwasher manufacturers.